While researching for my latest release, Fear No Evil, I jumped into all information I could find about gangs. Here's an exercept from an interesting article from Affluence and Gangs:
You live in the good neighborhood. All of your neighbors make great money, the kids all go to private school; you walk your dogs together, go to the gym together and mow your lawns on the same day thanks to your Home Owner's Association (HOA) rules. Does that make your neighborhood any less likely to have gang activity move in? On the other hand, does it make your neighborhood all the more likely to be able to hide it when it does?